1 infection targets , replication techniques
1.1 resident vs. non-resident viruses
1.2 macro viruses
1.3 boot sector viruses
1.4 email virus
infection targets , replication techniques
computer viruses infect variety of different subsystems on host computers , software. 1 manner of classifying viruses analyze whether reside in binary executables (such .exe or .com files), data files (such microsoft word documents or pdf files), or in boot sector of host s hard drive (or combination of of these).
resident vs. non-resident viruses
a memory-resident virus (or resident virus ) installs part of operating system when executed, after remains in ram time computer booted when shut down. resident viruses overwrite interrupt handling code or other functions, , when operating system attempts access target file or disk sector, virus code intercepts request , redirects control flow replication module, infecting target. in contrast, non-memory-resident virus (or non-resident virus ), when executed, scans disk targets, infects them, , exits (i.e. not remain in memory after done executing).
macro viruses
many common applications, such microsoft outlook , microsoft word, allow macro programs embedded in documents or emails, programs may run automatically when document opened. macro virus (or document virus ) virus written in macro language, , embedded these documents when users open file, virus code executed, , can infect user s computer. 1 of reasons dangerous open unexpected or suspicious attachments in e-mails. while not opening attachments in e-mails unknown persons or organizations can reduce likelihood of contracting virus, in cases, virus designed e-mail appears reputable organization (e.g., major bank or credit card company).
boot sector viruses
boot sector viruses target boot sector and/or master boot record (mbr) of host s hard drive or removable storage media (flash drives, floppy disks, etc.).
email virus
email virus – virus specifically, rather accidentally, uses email system spread. while virus infected files may accidentally sent email attachments, email viruses aware of email system functions. target specific type of email system (microsoft’s outlook commonly used), harvest email addresses various sources, , may append copies of email sent, or may generate email messages containing copies of attachments.
Comments
Post a Comment